From: "Jonathan T. Leighton" <jtlei...@udel.edu> Date: Sun, 12 Feb 2017 17:26:05 -0500
> Under some circumstances IPv6 datagrams are sent with IPv4-mapped IPv6 > addresses as the source. Given an IPv6 socket bound to an IPv4-mapped > IPv6 address, and an IPv6 destination address, both TCP and UDP will > will send packets using the IPv4-mapped IPv6 address as the source. Per > RFC 6890 (Table 20), IPv4-mapped IPv6 source addresses are not allowed > in an IP datagram. The problem can be observed by attempting to > connect() either a TCP or UDP socket, or by using sendmsg() with a UDP > socket. The patch is intended to correct this issue for all socket > types. > > linux follows the BSD convention that an IPv6 destination address > specified as in6addr_any is converted to the loopback address. > Currently, neither TCP nor UDP consider the possibility that the source > address is an IPv4-mapped IPv6 address, and assume that the appropriate > loopback address is ::1. The patch adds a check on whether or not the > source address is an IPv4-mapped IPv6 address and then sets the > destination address to either ::ffff:127.0.0.1 or ::1, as appropriate. Series applied, thanks.
